Class: Opal::Compiler

Inherits:
Object
  • Object
show all
Defined in:
opal/lib/opal/compiler.rb

Overview

Compiler is the main class used to compile ruby to javascript code. This class uses Parser to gather the sexp syntax tree for the ruby code, and then uses Node to step through the sexp to generate valid javascript.

Examples:

Opal::Compiler.new("ruby code").compile
# => "javascript code"

Accessing result

compiler = Opal::Compiler.new("ruby_code")
compiler.compile
compiler.result # => "javascript code"

Source Maps

compiler = Opal::Compiler.new("")
compiler.compile
compiler.source_map # => #<SourceMap:>

Constant Summary collapse

INDENT =

Generated code gets indented with two spaces on each scope

'  '
COMPARE =

All compare method nodes - used to optimize performance of math comparisons

%w[< > <= >=].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(source, options = {}) ⇒ Compiler

Returns a new instance of Compiler.


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# File 'opal/lib/opal/compiler.rb', line 183

def initialize(source, options = {})
  @source = source
  @indent = ''
  @unique = 0
  @options = options
  @comments = Hash.new([])
  @case_stmt = nil
  @option_values = {}
  @magic_comments = {}
end

Instance Attribute Details

#case_stmtObject (readonly)

Current case_stmt


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# File 'opal/lib/opal/compiler.rb', line 172

def case_stmt
  @case_stmt
end

#commentsObject (readonly)

Comments from the source code


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# File 'opal/lib/opal/compiler.rb', line 178

def comments
  @comments
end

#eof_contentObject (readonly)

Any content in END special construct


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# File 'opal/lib/opal/compiler.rb', line 175

def eof_content
  @eof_content
end

#fragmentsArray (readonly)

Returns all [Opal::Fragment] used to produce result.

Returns:

  • (Array)

    all [Opal::Fragment] used to produce result


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# File 'opal/lib/opal/compiler.rb', line 166

def fragments
  @fragments
end

#magic_commentsObject (readonly)

Magic comment flags extracted from the leading comments


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# File 'opal/lib/opal/compiler.rb', line 181

def magic_comments
  @magic_comments
end

#resultString (readonly)

Returns The compiled ruby code.

Returns:

  • (String)

    The compiled ruby code


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# File 'opal/lib/opal/compiler.rb', line 163

def result
  @result
end

#scopeObject

Current scope


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# File 'opal/lib/opal/compiler.rb', line 169

def scope
  @scope
end

Class Method Details

.compiler_option(name, config = {}) ⇒ Object

Defines a compiler option.

Parameters:

  • as: (Hash)

    a customizable set of options

  • default: (Hash)

    a customizable set of options

  • magic_comment: (Hash)

    a customizable set of options


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# File 'opal/lib/opal/compiler.rb', line 65

def self.compiler_option(name, config = {})
  method_name = config.fetch(:as, name)
  define_method(method_name) { option_value(name, config) }
end

.module_name(path) ⇒ Object


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# File 'opal/lib/opal/compiler.rb', line 56

def self.module_name(path)
  path = File.join(File.dirname(path), File.basename(path).split('.').first)
  Pathname(path).cleanpath.to_s
end

Instance Method Details

#arity_check?Boolean

adds an arity check to every method definition

Returns:

  • (Boolean)

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# File 'opal/lib/opal/compiler.rb', line 115

compiler_option :arity_check, default: false, as: :arity_check?

#compileString

Compile some ruby code to a string.

Returns:

  • (String)

    javascript code


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# File 'opal/lib/opal/compiler.rb', line 197

def compile
  parse

  @fragments = re_raise_with_location { process(@sexp).flatten }
  @fragments << fragment("\n", nil, s(:newline)) unless @fragments.last.code.end_with?("\n")

  @result = @fragments.map(&:code).join('')
end

#dynamic_require_severityObject

how to handle dynamic requires (:error, :warning, :ignore)


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# File 'opal/lib/opal/compiler.rb', line 133

compiler_option :dynamic_require_severity, default: :ignore, valid_values: %i[error warning ignore]

#enable_source_location?Object

Adds source_location for every method definition


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# File 'opal/lib/opal/compiler.rb', line 150

compiler_option :enable_source_location, default: false, as: :enable_source_location?

#error(msg, line = nil) ⇒ Object

This is called when a parsing/processing error occurs. This method simply appends the filename and curent line number onto the message and raises it.


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# File 'opal/lib/opal/compiler.rb', line 253

def error(msg, line = nil)
  error = ::Opal::SyntaxError.new(msg)
  error.location = Opal::OpalBacktraceLocation.new(file, line)
  raise error
end

#fileString

The filename to use for compiling this code. Used for FILE directives as well as finding relative require()

Returns:

  • (String)

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# File 'opal/lib/opal/compiler.rb', line 101

compiler_option :file, default: '(file)'

#fragment(str, scope, sexp = nil) ⇒ Object


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# File 'opal/lib/opal/compiler.rb', line 292

def fragment(str, scope, sexp = nil)
  Fragment.new(str, scope, sexp)
end

#freezing?Boolean

Deprecated.

stubs out #freeze and #frozen?

Returns:

  • (Boolean)

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# File 'opal/lib/opal/compiler.rb', line 123

compiler_option :freezing, default: true, as: :freezing?

#handle_block_given_call(sexp) ⇒ Object


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# File 'opal/lib/opal/compiler.rb', line 485

def handle_block_given_call(sexp)
  @scope.uses_block!
  if @scope.block_name
    fragment("(#{@scope.block_name} !== nil)", scope, sexp)
  elsif (scope = @scope.find_parent_def) && scope.block_name
    fragment("(#{scope.block_name} !== nil)", scope, sexp)
  else
    fragment('false', scope, sexp)
  end
end

#handlersObject


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# File 'opal/lib/opal/compiler.rb', line 392

def handlers
  @handlers ||= Opal::Nodes::Base.handlers
end

#helper(name) ⇒ Object

Use the given helper


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# File 'opal/lib/opal/compiler.rb', line 327

def helper(name)
  helpers << name
end

#helpersSet<Symbol>

Any helpers required by this file. Used by Nodes::Top to reference runtime helpers that are needed. These are used to minify resulting javascript by keeping a reference to helpers used.

Returns:

  • (Set<Symbol>)

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# File 'opal/lib/opal/compiler.rb', line 234

def helpers
  @helpers ||= Set.new(
    magic_comments[:helpers].to_s.split(',').map { |h| h.strip.to_sym }
  )
end

#in_caseObject


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# File 'opal/lib/opal/compiler.rb', line 366

def in_case
  return unless block_given?
  old = @case_stmt
  @case_stmt = {}
  yield
  @case_stmt = old
end

#in_whileObject

Used when we enter a while statement. This pushes onto the current scope's while stack so we know how to handle break, next etc.


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# File 'opal/lib/opal/compiler.rb', line 358

def in_while
  return unless block_given?
  @while_loop = @scope.push_while
  result = yield
  @scope.pop_while
  result
end

#in_while?Boolean

Returns true if the parser is curently handling a while sexp, false otherwise.

Returns:

  • (Boolean)

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# File 'opal/lib/opal/compiler.rb', line 376

def in_while?
  @scope.in_while?
end

#indentObject

To keep code blocks nicely indented, this will yield a block after adding an extra layer of indent, and then returning the resulting code after reverting the indent.


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# File 'opal/lib/opal/compiler.rb', line 334

def indent
  indent = @indent
  @indent += INDENT
  @space = "\n#{@indent}"
  res = yield
  @indent = indent
  @space = "\n#{@indent}"
  res
end

#inline_operators?Object

are operators compiled inline


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# File 'opal/lib/opal/compiler.rb', line 143

compiler_option :inline_operators, default: true, as: :inline_operators?

#irb?Object

compile top level local vars with support for irb style vars


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# File 'opal/lib/opal/compiler.rb', line 128

compiler_option :irb, default: false, as: :irb?

#method_callsObject

Method calls made in this file


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# File 'opal/lib/opal/compiler.rb', line 246

def method_calls
  @method_calls ||= Set.new
end

#method_missing?Boolean

adds method stubs for all used methods in file

Returns:

  • (Boolean)

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# File 'opal/lib/opal/compiler.rb', line 108

compiler_option :method_missing, default: true, as: :method_missing?

#operator_helpersObject

Operator helpers


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# File 'opal/lib/opal/compiler.rb', line 241

def operator_helpers
  @operator_helpers ||= Set.new
end

#option_value(name, config) ⇒ Object

Fetches and memoizes the value for an option.


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# File 'opal/lib/opal/compiler.rb', line 71

def option_value(name, config)
  return @option_values[name] if @option_values.key? name

  default_value = config[:default]
  valid_values  = config[:valid_values]
  magic_comment = config[:magic_comment]

  value = @options.fetch(name, default_value)

  if magic_comment && @magic_comments.key?(name)
    value = @magic_comments.fetch(name)
  end

  if valid_values && !valid_values.include?(value)
    raise(
      ArgumentError,
      "invalid value #{value.inspect} for option #{name.inspect} " \
      "(valid values: #{valid_values.inspect})"
    )
  end

  @option_values[name] = value
end

#parseObject


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# File 'opal/lib/opal/compiler.rb', line 206

def parse
  @buffer = ::Opal::Parser::SourceBuffer.new(file, 1)
  @buffer.source = @source

  @parser = Opal::Parser.default_parser

  sexp, comments, tokens = re_raise_with_location { @parser.tokenize(@buffer) }

  @sexp = s(:top, sexp || s(:nil))
  @comments = ::Parser::Source::Comment.associate_locations(sexp, comments)
  @magic_comments = MagicComments.parse(sexp, comments)
  @eof_content = EofContent.new(tokens, @source).eof
end

#parse_comments?Object

Adds comments for every method definition


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# File 'opal/lib/opal/compiler.rb', line 160

compiler_option :parse_comments, default: false, as: :parse_comments?

#parser_indentObject

Instances of Scope can use this to determine the current scope indent. The indent is used to keep generated code easily readable.


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# File 'opal/lib/opal/compiler.rb', line 281

def parser_indent
  @indent
end

#process(sexp, level = :expr) ⇒ Object

Process the given sexp by creating a node instance, based on its type, and compiling it to fragments.


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# File 'opal/lib/opal/compiler.rb', line 382

def process(sexp, level = :expr)
  return fragment('', scope) if sexp.nil?

  if handler = handlers[sexp.type]
    return handler.new(sexp, level, self).compile_to_fragments
  else
    error "Unsupported sexp: #{sexp.type}"
  end
end

#re_raise_with_locationObject


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# File 'opal/lib/opal/compiler.rb', line 259

def re_raise_with_location
  yield
rescue StandardError, ::Opal::SyntaxError => error
  opal_location = ::Opal.opal_location_from_error(error)
  opal_location.path = file
  opal_location.label ||= @source.lines[opal_location.line.to_i - 1].strip
  new_error = ::Opal::SyntaxError.new(error.message)
  new_error.set_backtrace error.backtrace
  ::Opal.add_opal_location_to_error(opal_location, new_error)
  raise new_error
end

#requirable?Object

Prepare the code for future requires


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# File 'opal/lib/opal/compiler.rb', line 138

compiler_option :requirable, default: false, as: :requirable?

#required_treesObject

An array of trees required in this file (typically by calling #require_tree)


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# File 'opal/lib/opal/compiler.rb', line 403

def required_trees
  @required_trees ||= []
end

#requiresObject

An array of requires used in this file


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# File 'opal/lib/opal/compiler.rb', line 397

def requires
  @requires ||= []
end

#returns(sexp) ⇒ Object

The last sexps in method bodies, for example, need to be returned in the compiled javascript. Due to syntax differences between javascript any ruby, some sexps need to be handled specially. For example, if statemented cannot be returned in javascript, so instead the "truthy" and "falsy" parts of the if statement both need to be returned instead.

Sexps that need to be returned are passed to this method, and the alterned/new sexps are returned and should be used instead. Most sexps can just be added into a s(:return) sexp, so that is the default action if no special case is required.


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# File 'opal/lib/opal/compiler.rb', line 418

def returns(sexp)
  return returns s(:nil) unless sexp

  case sexp.type
  when :undef
    # undef :method_name always returns nil
    returns s(:begin, sexp, s(:nil))
  when :break, :next, :redo
    sexp
  when :yield
    sexp.updated(:returnable_yield, nil)
  when :when
    *when_sexp, then_sexp = *sexp
    sexp.updated(nil, [*when_sexp, returns(then_sexp)])
  when :rescue
    body_sexp, *resbodies, else_sexp = *sexp

    resbodies = resbodies.map do |resbody|
      returns(resbody)
    end

    if else_sexp
      else_sexp = returns(else_sexp)
    end

    sexp.updated(
      nil, [
        returns(body_sexp),
        *resbodies,
        else_sexp
      ]
    )
  when :resbody
    klass, lvar, body = *sexp
    sexp.updated(nil, [klass, lvar, returns(body)])
  when :ensure
    rescue_sexp, ensure_body = *sexp
    sexp = sexp.updated(nil, [returns(rescue_sexp), ensure_body])
    s(:js_return, sexp)
  when :begin, :kwbegin
    # Wrapping last expression with s(:js_return, ...)
    *rest, last = *sexp
    sexp.updated(nil, [*rest, returns(last)])
  when :while, :until, :while_post, :until_post
    sexp
  when :return, :js_return, :returnable_yield
    sexp
  when :xstr
    sexp.updated(nil, [s(:js_return, *sexp.children)])
  when :if
    cond, true_body, false_body = *sexp
    sexp.updated(
      nil, [
        cond,
        returns(true_body),
        returns(false_body)
      ]
    )
  else
    s(:js_return, sexp).updated(
      nil,
      nil,
      location: sexp.loc,
    )
  end
end

#s(type, *children) ⇒ Object

Create a new sexp using the given parts. Even though this just returns an array, it must be used incase the internal structure of sexps does change.


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# File 'opal/lib/opal/compiler.rb', line 288

def s(type, *children)
  ::Opal::AST::Node.new(type, children)
end

#source_mapOpal::SourceMap

Returns a source map that can be used in the browser to map back to original ruby code.

Parameters:

  • source_file (String)

    optional source_file to reference ruby source

Returns:


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# File 'opal/lib/opal/compiler.rb', line 225

def source_map
  ::Opal::SourceMap::File.new(@fragments, file, @source)
end

#unique_temp(name) ⇒ Object

Used to generate a unique id name per file. These are used mainly to name method bodies for methods that use blocks.


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# File 'opal/lib/opal/compiler.rb', line 298

def unique_temp(name)
  name = name.to_s
  if name && !name.empty?
    name = name
           .to_s
           .gsub('<=>', '$lt_eq_gt')
           .gsub('===', '$eq_eq_eq')
           .gsub('==', '$eq_eq')
           .gsub('=~', '$eq_tilde')
           .gsub('!~', '$excl_tilde')
           .gsub('!=', '$not_eq')
           .gsub('<=', '$lt_eq')
           .gsub('>=', '$gt_eq')
           .gsub('=', '$eq')
           .gsub('?', '$ques')
           .gsub('!', '$excl')
           .gsub('/', '$slash')
           .gsub('%', '$percent')
           .gsub('+', '$plus')
           .gsub('-', '$minus')
           .gsub('<', '$lt')
           .gsub('>', '$gt')
           .gsub(/[^\w\$]/, '$')
  end
  unique = (@unique += 1)
  "#{'$' unless name.start_with?('$')}#{name}$#{unique}"
end

#use_strict?Object

Enables JavaScript's strict mode (i.e., adds 'use strict'; statement)


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# File 'opal/lib/opal/compiler.rb', line 155

compiler_option :use_strict, default: false, as: :use_strict?, magic_comment: true

#warning(msg, line = nil) ⇒ Object

This is called when a parsing/processing warning occurs. This method simply appends the filename and curent line number onto the message and issues a warning.


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# File 'opal/lib/opal/compiler.rb', line 274

def warning(msg, line = nil)
  warn "warning: #{msg} -- #{file}:#{line}"
end

#with_tempObject

Temporary varibales will be needed from time to time in the generated code, and this method will assign (or reuse) on while the block is yielding, and queue it back up once it is finished. Variables are queued once finished with to save the numbers of variables needed at runtime.


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# File 'opal/lib/opal/compiler.rb', line 349

def with_temp
  tmp = @scope.new_temp
  res = yield tmp
  @scope.queue_temp tmp
  res
end